Average house prices in the North West fell 0.7% in July to £118,360 according to the latest monthly figures from the Land Registry.
The annual change compared to July 2009 was 0.3%. Nationally the annual change was an increase of 6.7% to £166,798.
The North West was among the worst performing regions last month, with only Wales's 1.1% fall greater.
There were monthly rises in London, South West, Yokshire, West Midlands, South East and East Midlands.
During May 2010, the number of completed house sales in England and Wales rose by 8% to 49,412 from 45,814 in May 2009. The number of properties sold in England and Wales for over £1m increased by 67% between May 2009 and May 2010, from 255 to 426.